Systems and methods for an enhanced stable approach monitor

ABSTRACT

Alerting systems and methods for an enhanced approach monitor are provided. The system is configured to: determine a missed approach altitude (MAA), an intended configuration, and target approach speed, each being related to the intended approach procedure and aircraft specific data. At a decision point defined as a co-occurrence of (a) the RT distance is substantially equal to or less than a distance threshold, and (b) the RT altitude is substantially equal to the MAA, the system identifies go-around scenarios, such as when (i) the RT speed exceeds the target approach speed, or (ii) the RT configuration is not equal to the intended configuration, or (iii) an RT approach path angle exceeds the target angle. The system issues a go-around alert based on whether the aircraft can perform a go-around operation, as determined based on aircraft performance data and terrain data.

TECHNICAL FIELD

The technical field generally relates to stable approach monitoring, andmore particularly relates to systems and methods for alerting for anaircraft approaching a target runway.

BACKGROUND

The approach and landing flight phases continue to dominate aviationsafety considerations. A stabilized approach to a target runway maygenerally be defined in established stabilized approach standardoperating procedures that include minimum acceptable criteria, such asapproach speed, approach angles, and equipment configuration. The pilotand/or flight crew monitors the aircraft's performance and configurationin comparison to the established stabilized approach standard operatingprocedures. When the aircraft approaching the target runway is notmeeting the minimum acceptable criteria at a designated altitude, thepilot is expected to respond by performing a go-around operation.

The minimum acceptable criteria vary in detail, but the Flight SafetyFoundation (FSF) stabilized approach criteria are the key internationalstandards that were established in 1999. The FSF criteria generallystate several altitudes for which the approach must be stabilized, whereeach altitude applies to a different approach scenario. Performing ago-around operation when required ensures that an aircraft is notapproaching the target runway too fast, at too steep of an angle,arriving too high above a runway threshold, or not otherwise incorrectlyconfigured for landing and deceleration.

In some instances, pilots believe that the go-around criteria for astable approach are too conservative and may disregard indicators forthe need to conduct a go-around; and, in some instances, land theaircraft without any negative consequences. Indeed, research has shownthat there is a lower than expected compliance with stabilized approachstandard operating procedures. Therefore, improved flight deck systemsthat provide go-around guidance that pilots trust and will result inincreased compliance is a technical problem to address.

Accordingly, improved systems and methods for generating go-aroundalerts for the aircraft approaching the target runway are desirable. Thedesirable enhanced stable approach monitor is an alert system thatutilizes aircraft-specific data in combination with approach proceduredata and terrain data to generate and issue an enhanced go-around alert.The desirable alert system inspires greater compliance with go-aroundalerts due to its improved determinations. The following disclosureprovides these technological enhancements, in addition to addressingrelated issues.

BRIEF SUMMARY

This summary is provided to describe select concepts in a simplifiedform that are further described in the Detailed Description. Thissummary is not intended to identify key or essential features of theclaimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

Provided is an alerting system for an aircraft approaching a targetrunway. The alerting system includes: a source of approachminimum/minima data including a target altitude; a source of an intendedapproach procedure; a source of real time (RT) aircraft state dataincluding an RT location, an RT altitude and an RT speed; a source ofaircraft specific data including RT configuration data and respectiveperformance data; a source of terrain data; and a control moduleoperationally coupled to the source of approach minimum/minima data, thesource of the intended approach procedure, the source of RT aircraftstate data, the source of aircraft specific data, and the source ofterrain data, the control module configured to: determine a missedapproach altitude (MAA), corresponding target angle, an intendedconfiguration, and target approach speed, each being related to theintended approach procedure and aircraft specific data; upon determiningthat the RT altitude is substantially equal to the MAA, or a RT distanceis less than or equal to a distance threshold, identify each of thefollowing situations as a go-around scenario: (i) when the RT speedexceeds the target approach speed, (ii) when the RT configuration is notequal to the intended configuration, and (iii) when an RT approach pathangle exceeds the target angle; and upon recognizing the occurrence of ago-around scenario, determine when (i) the RT speed exceeds the targetapproach speed, or (ii) the RT configuration is not equal to theintended configuration, or (iii) an RT approach path angle exceeds thetarget angle; and determine whether the aircraft can perform a go-aroundoperation based at least in part upon the aircraft performance data andthe terrain data; and issue a go-around alert when the aircraft canperform the go-around operation; and prevent a go-around alert when theaircraft cannot perform the go-around operation.

Also provided is a method for alerting for an aircraft approaching atarget runway, including: at a control module comprising a processor anda memory, receiving, from a source of approach minimum data, a targetaltitude; receiving, from a flight management system (FMS), an intendedapproach procedure; receiving, from a navigation system, real time (RT)aircraft state data including an RT location, an RT altitude and an RTspeed; receiving from an avionics system, RT configuration data;receiving aircraft specific data including configuration data andrespective performance data; receiving terrain data from a terraindatabase; determining a missed approach altitude (MAA), correspondingtarget angle, an intended configuration, and target approach speed, eachbeing related to the intended approach procedure and aircraft specificdata; upon determining that the RT altitude is substantially equal tothe MAA, or a RT distance is less than or equal to a distance threshold,identify each of the following situations as a go-around scenario: (i)when the RT speed exceeds the target approach speed, (ii) when the RTconfiguration is not equal to the intended configuration, and (iii) whenan RT approach path angle exceeds the target angle; and upon recognizingthe occurrence of a go-around scenario, determine when (i) the RT speedexceeds the target approach speed, or (ii) the RT configuration is notequal to the intended configuration, or (iii) an RT approach path angleexceeds the target angle; and determining whether the aircraft canperform a go-around operation based at least in part upon the aircraftperformance data and the terrain data; and issuing a go-around alertwhen the aircraft can perform the go-around operation; and preventing ago-around alert when the aircraft cannot perform the go-aroundoperation.

An enhanced approach monitor is also provided. The enhanced approachmonitor includes: a source of approach minimum data including a targetaltitude; a source of an intended approach procedure; a source of realtime (RT) aircraft state data including an RT location, an RT altitudeand an RT speed; a source of aircraft specific data including RTconfiguration data and respective performance data; a source of terraindata; and a control module operationally coupled to the source ofapproach minimum data, the source of the intended approach procedure,the source of RT aircraft state data, the source of aircraft specificdata, and the source of terrain data, the control module configured to:determine a missed approach altitude (MAA), corresponding target angle,an intended configuration, and target approach speed, each being relatedto the intended approach procedure and aircraft specific data; upondetermining that the RT altitude is substantially equal to the MAA, or aRT distance is less than or equal to a distance threshold, identify eachof the following situations as a go-around scenario: (i) when the RTspeed exceeds the target approach speed, (ii) when the RT configurationis not equal to the intended configuration, and (iii) when an RTapproach path angle exceeds the target angle; and upon recognizing theoccurrence of a go-around scenario, determine when (i) the RT speedexceeds the target approach speed, or (ii) the RT configuration is notequal to the intended configuration, or (iii) an RT approach path angleexceeds the target angle; and determine whether the aircraft can performa go-around operation based at least in part upon the aircraftperformance data and the terrain data; and issue a go-around alert whenthe aircraft can perform the go-around operation; and prevent ago-around alert when the aircraft cannot perform the go-aroundoperation; and a display system operationally coupled to the controlmodule, and wherein: the control module is further configured to issuethe go-around alert by generating display commands for the displaysystem to render symbology on an image; and the display system isconfigured to render the symbology, responsive to the display commands.

Furthermore, other desirable features and characteristics of the systemand method will become apparent from the subsequent detailed descriptionand the appended claims, taken in conjunction with the accompanyingdrawings and the preceding background.

BRIEF DESCRIPTION OF THE DRAWINGS

The present application will hereinafter be described in conjunctionwith the following drawing figures, wherein like numerals denote likeelements, and:

FIG. 1 is a block diagram of alerting system for an aircraft approachinga target runway, in accordance with an exemplary embodiment;

FIG. 2 is an illustration depicting an application for the alertingsystem for an aircraft approaching a target runway, in accordance withan exemplary embodiment;

FIG. 3 is an image as may be found on a display system, showing ago-around alert, in accordance with an exemplary embodiment; and

FIG. 4 is a flow chart for a method for alerting for an aircraftapproaching a target runway, in accordance with an exemplary embodiment.

DETAILED DESCRIPTION

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter or theapplication and uses of such embodiments. As used herein, the word“exemplary” means “serving as an example, instance, or illustration.”Thus, any embodiment described herein as “exemplary” is not necessarilyto be construed as preferred or advantageous over other embodiments. Theembodiments described herein are exemplary embodiments provided toenable persons skilled in the art to make or use the invention and notto limit the scope of the invention that is defined by the claims.Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the preceding technical field, background,summary, or the following detailed description.

As mentioned, responding to a go-around alert by performing a go-aroundoperation, ensures that a pilot is not approaching the target runway toofast, at too steep of an angle, arriving too high above a runwaythreshold, or not otherwise incorrectly configured for landing anddeceleration. Since research has shown that there is a lower thanexpected compliance with stabilized approach criteria for go-arounds, atechnical problem presented is the enhanced generation of go-aroundalert that pilots trust and will promote increased compliance. Exemplaryembodiments provide a technical solution to this problem in the form ofa control module (FIG. 1, 104) embodying novel rules that combine andconvert existing approach procedure data, approach minimums data,aircraft specific data, and terrain data to generate and issue go-aroundalerts. The figures and descriptions below provide more detail.

Turning now to FIG. 1, in an embodiment, the alerting system 102 for anaircraft approaching a target runway (also referred to herein as anenhanced approach monitor, and as “system” 102) is generally associatedwith a mobile platform 100. In various embodiments, the mobile platform100 is an aircraft, and is referred to as aircraft 100. The system 102embodies a control module 104. Although the control module 104 is shownas an independent functional block, onboard the aircraft 100, in someembodiments, the control module 104 is integrated within a preexistingmobile platform management system, avionics system, cockpit displaysystem (CDS), flight controls system (FCS), or aircraft flightmanagement system (FMS). In some embodiments, the control module 104,user input device 120, and display system 118 are configured as acontrol display unit (CDU). In other embodiments, the control module 104may exist in an electronic flight bag (EFB) or portable electronicdevice (PED), such as a tablet, cellular phone, or the like. Inembodiments in which the control module is within an EFB or a PED, thedisplay system 118 and user input device 120 may also be part of the EFBor PED.

The control module 104 may be operationally coupled to any combinationof the following aircraft systems, which are generally on-board systems:a source of approach minimum data 106, a source of an intended approachprocedure 108; a source of real time (RT) aircraft state data 110; asource of RT configuration data 112; a source of aircraft specific data116; a source of terrain data 124; a display system 118; and, a userinput device 120. In various embodiments, a communication system andfabric 126 may reside onboard and operationally couple various on-boardsystems and external sources 122 to the control module 104. Thefunctions of these aircraft systems, and their interaction, aredescribed in more detail below.

The intended approach procedure 108 may be a selection based onprocessing information from a variety of sources. In variousembodiments, the intended approach procedure 108 may be provided by aflight management system (FMS), in communication with a navigationdatabase. In other embodiments, the intended approach procedure 108 maybe provided by a user input device 120. Examples of approach proceduresinclude precision approaches and non-precision approaches includinginstrument landing system (ILS) procedures, circling approaches, and thelike. Each approach procedure has a published approach minimum data 106.

The approach minimum data 106 may be part of a series of intendedgeospatial midpoints between a cruise altitude and a landing, inaddition to intended performance data associated with each of thegeospatial midpoints (non-limiting examples of the performance datainclude intended navigation data, such as: intended airspeed, intendedaltitude, intended acceleration, intended flight path angle, and thelike). In various embodiments, the source of the approach minimum data106 is a navigation database (NavDB). The NavDB is a storage locationthat may also maintain a database of flight plans, and/or informationregarding terrain and airports and/or other potential landing locations(or destinations) for the aircraft 100. The approach minimum data 106includes a target altitude that may be variously referred to as adecision height (DH), a decision altitude (DA), a missed approach point(MAP), and the like. Pilots are trained to use and understand thepublished approach minimum data 106. In some embodiments, the targetaltitude is based on data from a barometric altimeter reference bug,which the control module 104 processes with novel rules (program 162) togenerate the target altitude.

Real-time (RT) aircraft state data may include any of: an instantaneouslocation (e.g., the latitude, longitude, orientation), an instantaneoustrack (i.e., the direction the aircraft is traveling in relative to somereference), a RT flight path angle, a RT vertical speed, a RT groundspeed, a RT instantaneous altitude (or height above ground level), and acurrent phase of flight of the aircraft 100. As used herein, “real-time”is interchangeable with current, instantaneous, and actual (as opposedto intended). In some embodiments, the RT aircraft state data isgenerated by a navigation system. The source of aircraft state data 110may be realized as including a global positioning system (GPS), inertialreference system (IRS), or a radio-based navigation system (e.g., VHFomni-directional radio range (VOR) or long-range aid to navigation(LORAN)), and may include one or more navigational radios or othersensors suitably configured to support operation of the FMS, as will beappreciated in the art. Aircraft state data is sometimes referred to asnavigation data. In various embodiments, the RT aircraft state data ismade available by way of the communication system and fabric 126, soother components, such as the control module 104 and the display system118, may further process and/or handle the aircraft state data.

Aircraft specific data 116 generally includes, for aircraft 100, datathat is specific to components and systems; such as, an inventory ofcomponents, settings of components, performance ratings of components,and the like. For example, aircraft specific data may include the typeof engine on the aircraft 100, its available thrust levels andperformance rating at respective thrust levels, its performance inreverse thrust, its age, its maintenance history, and the like. Inanother example, aircraft specific data may include the type of flaps onthe aircraft 100, the number of configurations supported by the flaps,and the performance rating for each of the configurations.

Aircraft specific data further includes aircraft RT configuration data112 and aircraft performance data 114. Aircraft RT configuration data112 constitutes a current or real-time configuration or setting for eachof various on-board avionics systems. Specific to this disclosure, arethe aircraft flaps, landing gear and engine and, at any given time,their combined status or settings may be referred to as RT aircraftconfiguration data. During operation, each of the various avionicssystems self-report or provide respective real-time (RT) performancedata and sensed data for further processing. Therefore, examples of theaircraft performance data 114 include: RT engine thrust level, RT flapconfiguration, RT braking status/setting, and the like. As may beappreciated, each of the on-board avionics systems may therefore includea variety of on-board detection sensors and may be operationally coupledto the control module 104, central management computer, or FMS.

Over time, the aircraft 100 accumulates a performance history. Aircraft100 performance data 114 may include historical stopping anddeceleration distance data as related to various configurations, weight,and the age or wear of aircraft components. In various embodiments,Aircraft performance data 114 may include historical approachperformance data for various aircraft configurations. Aircraftperformance data 114 may be stored in a database onboard the aircraft ormay be provided via an eternal source 122. In various embodiments, thesource of aircraft specific data 116 and aircraft performance data 114is the same, and may be external of the aircraft 100, and may further beupdated remotely. When a go-around scenario has been identified, thecontrol module 104 may reference and process aircraft performance data114 and terrain data 124 in addition to processing RT state data 110 andRT configuration data in order to determine whether determine whetherthe aircraft 100 can perform a respective go-around operation.

Terrain data 124 includes topographical information for the airport andsurrounding environment. A source of terrain data 124 may be a terraindatabase or an enhanced ground proximity warning system (EGPWS) terraindatabase. External sources 122 may also communicate with the aircraft100 and the control module 104. External sources may include or provide:notices to airmen (NOTAM), traffic data system(s); air traffic control(ATC); and a variety of other radio inputs, such as source(s) of theradio signals used by the an instrument landing system (ILS), andweather and surface data sources, such as a source for meteorologicalterminal aviation weather reports (METARS), automatic terminalinformation service (ATIS), datalink ATIS (D-ATIS), automatic surfaceobserving system (ASOS).

In various embodiments, communication between aircraft 100 subsystems ismanaged by a communication system and fabric 126. The communicationsystem and fabric 126 is configured to support instantaneous (i.e., realtime or current) communications between onboard systems (i.e., thenavigation system, the navigation database, the various avionicssystems, the FMS), the control module 104, and the one or more externaldata source(s) 122. As a functional block, the communication system andfabric 126 may represent one or more transmitters, receivers, and thesupporting communications hardware and software required for componentsof the system 102 to communicate as described herein. In variousembodiments, the communication system and fabric 126 may have additionalcommunications not directly relied upon herein, such as bidirectionalpilot-to-ATC (air traffic control) communications via a datalink;support for an automatic dependent surveillance broadcast system(ADS-B); a communication management function (CMF) uplink; a terminalwireless local area network (LAN) unit (TWLU); an instrument landingsystem (ILS); and, any other suitable radio communication system thatsupports communications between the aircraft 100 and the variousexternal source(s). In various embodiments, the control module 104 andcommunication system and fabric 126 also support controller pilot datalink communications (CPDLC), such as through an aircraft communicationaddressing and reporting system (ACARS) router; in various embodiments,this feature may be referred to as a communications management unit(CMU) or communications management function (CMF). In summary, thecommunication system and fabric 126 may allow the aircraft 100 and thecontrol module 104 to receive information that would otherwise beunavailable to the pilot and/or co-pilot using only the onboard systems.

The user input device 120 and the control module 104 are cooperativelyconfigured to allow a user (e.g., a pilot, co-pilot, or crew member) tointeract with display devices 20 in the display system 118 and/or otherelements of the system 102, as described in greater detail below.Depending on the embodiment, the user input device 120 may be realizedas a cursor control device (CCD), keypad, touchpad, keyboard, mouse,touch panel (or touchscreen), joystick, knob, line select key, voicecontroller, gesture controller, or another suitable device adapted toreceive input from a user. When the user input device 120 is configuredas a touchpad or touchscreen, it may be integrated with the displaysystem 118. As used herein, the user input device 120 may be used tomodify or upload the program product 166, override the program when it'srunning, etc. In various embodiments, the display system 118 and userinput device 120 are onboard the aircraft 100 and are also operationallycoupled to the communication system and fabric 126.

In various embodiments, the control module 104, alone, or as part of acentral management computer (CMS) or a flight management system (FMS),executes instructions 160 and thereby draws upon data and informationfrom a navigation system and a NavDB to provide real-time flightguidance for aircraft 100. The real time flight guidance may be providedto a user by way of commands for the display system 118, an audiosystem, or the like. For example, the control module 104 may compare aninstantaneous (actual) position and heading of the aircraft 100 with theprescribed or intended flight plan data for the aircraft 100 andgenerate display commands to render images 22 showing these features.The control module 104 may further associate a respective airport, itsgeographic location, runways (and their respective orientations and/ordirections), instrument procedures (e.g., approach procedures, arrivalroutes and procedures, takeoff procedures, and the like), airspacerestrictions, and/or other information or attributes associated with therespective airport (e.g., widths and/or weight limits of taxi paths, thetype of surface of the runways or taxi path, and the like) with theinstantaneous position and heading of the aircraft 100 and/or with thenavigation plan for the aircraft 100.

The control module 104 generates display commands for the display system118 to cause the display device 20 to render thereon the image 22,comprising various graphical user interface elements, tables, icons,alerts, menus, buttons, and pictorial images, as described herein. Thedisplay system 118 is configured to continuously receive and process thedisplay commands from the control module 104. The display system 118includes a display device 20 for presenting an image 22. In variousembodiments described herein, the display system 118 includes asynthetic vision system (SVS), and the image 22 is a SVS image. Inexemplary embodiments, the display device 20 is realized on one or moreelectronic display devices configured as any combination of: a head updisplay (HUD), an alphanumeric display, a vertical situation display(VSD) and a lateral navigation display (ND).

Renderings on the display system 118 may be processed by a graphicssystem, components of which may be integrated into the display system118 and/or be integrated within the control module 104. Display methodsinclude various types of computer generated symbols, text, and graphicinformation representing, for example, pitch, heading, flight path,airspeed, altitude, runway information, waypoints, targets, obstacles,terrain, and required navigation performance (RNP) data in anintegrated, multi-color or monochrome form. Display methods also includevarious formatting techniques for visually distinguishing objects androutes from among other similar objects and routes. In an embodiment,the Bokeh effect is used for emphasizing relevant signage with respectto remaining signage. The control module 104 may be said to displayvarious images and selectable options described herein. In practice,this may mean that the control module 104 generates display commands,and, responsive to receiving the display commands from the controlmodule 104, the display system 118 displays, renders, or otherwisevisually conveys on the display device 20, the graphical imagesassociated with operation of the aircraft 100, and specifically, thegraphical images as directed by the control module 104.

In various embodiments, the source of terrain data 124 additionallyincludes a runway awareness and advisory system (RAAS) database and anAerodrome Mapping Database (AMDB). In various embodiments, each of thesemay include an airport features database, having therein maps andgeometries, including runway records with corresponding runway thresholdlocations. The AMDB may also include airport status data for the runwaysand/or taxi paths at the airport; the airport status data indicatingoperational status and directional information for the taxi paths (orportions thereof).

The control module 104 performs the functions of the system 102. As usedherein, the term “module” refers to any means for facilitatingcommunications and/or interaction between the elements of the system 102and performing additional processes, tasks and/or functions to supportoperation of the system 102, as described herein. In variousembodiments, the control module 104 may be any hardware, software,firmware, electronic control component, processing logic, and/orprocessor device, individually or in any combination. Depending on theembodiment, the control module 104 may be implemented or realized with ageneral purpose processor (shared, dedicated, or group) controller,microprocessor, or microcontroller, and memory that executes one or moresoftware or firmware programs; a content addressable memory; a digitalsignal processor; an application specific integrated circuit (ASIC), afield programmable gate array (FPGA); any suitable programmable logicdevice; combinational logic circuit including discrete gates ortransistor logic; discrete hardware components and memory devices;and/or any combination thereof, designed to perform the functionsdescribed herein.

Accordingly, in FIG. 1, an embodiment of the control module 104 isdepicted as a computer system including a processor 150 and a memory152. The processor 150 may comprise any type of processor or multipleprocessors, single integrated circuits such as a microprocessor, or anysuitable number of integrated circuit devices and/or circuit boardsworking in cooperation to carry out the described operations, tasks, andfunctions by manipulating electrical signals representing data bits atmemory locations in the system memory, as well as other processing ofsignals. The memory 152 may comprise RAM memory, ROM memory, flashmemory, registers, a hard disk, or another suitable non-transitory shortor long-term storage media capable of storing computer-executableprogramming instructions or other data for execution. The memory 152 maybe located on and/or co-located on the same computer chip as theprocessor 150. Generally, the memory 152 maintains data bits and may beutilized by the processor 150 as storage and/or a scratch pad duringoperation. Information in the memory 152 may be organized and/orimported from an external data source 50 during an initialization stepof a process; it may also be programmed via a user input device 120. Insome embodiments, the database 156 is part of the memory 152. In someembodiments, the airport features data, the terrain data 124, and theaircraft specific data 116 are pre-loaded into the memory 152 or thedatabase 156, and are, therefore, internal to the control module 104.

The novel program 162 includes rules and instructions which, whenexecuted, convert the processor 150/memory 152/database 156configuration into the novel control module 104, which is a novel“aircraft approaching a target runway alerting” control module thatperforms the functions, techniques, and processing tasks associated withthe operation of the system 102. Novel program 162 and associated storedvariables 164 may be stored in a functional form on computer readablemedia, for example, as depicted, in memory 152. While the depictedexemplary embodiment is described in the context of a fully functioningcomputer system, those skilled in the art will recognize that themechanisms of the present disclosure are capable of being distributed asa program product 166. As a program product 166, one or more types ofnon-transitory computer-readable signal bearing media may be used tostore and distribute the program 162, such as a non-transitory computerreadable medium bearing the program 162 and containing thereinadditional computer instructions for causing a computer processor (suchas the processor 150) to load and execute the program 162. Such aprogram product 166 may take a variety of forms, and the presentdisclosure applies equally regardless of the type of computer-readablesignal bearing media used to carry out the distribution. Examples ofsignal bearing media include: recordable media such as floppy disks,hard drives, memory cards and optical disks, and transmission media suchas digital and analog communication links. It will be appreciated thatcloud-based storage and/or other techniques may also be utilized incertain embodiments.

In various embodiments, the processor/memory unit of the control module104 may be communicatively coupled (via a bus 155) to an input/output(I/O) interface 154, and a database 156. The bus 155 serves to transmitprograms, data, status and other information or signals between thevarious components of the control module 104. The bus 155 can be anysuitable physical or logical means of connecting computer systems andcomponents. This includes, but is not limited to, direct hard-wiredconnections, fiber optics, infrared and wireless bus technologies.

The I/O interface 154 enables intra control module 104 communication, aswell as communications between the control module 104 and other system102 components, and between the control module 104 and the external datasources via the communication system and fabric 126. The I/O interface154 may include one or more network interfaces and can be implementedusing any suitable method and apparatus. In various embodiments, the I/Ointerface 154 is configured to support communication from an externalsystem driver and/or another computer system. In one embodiment, the I/Ointerface 154 is integrated with the communication system and fabric 126and obtains data from external data source(s) directly. Also, in variousembodiments, the I/O interface 154 may support communication withtechnicians, and/or one or more storage interfaces for direct connectionto storage apparatuses, such as the database 156.

During operation, the processor 150 loads and executes one or moreprograms, algorithms and rules embodied as instructions and applications160 contained within the memory 152 and, as such, controls the generaloperation of the control module 104 as well as the system 102. Inexecuting the process described herein, the processor 150 specificallyloads the instructions embodied in the program 162, thereby beingprogrammed with program 162. During execution of program 162, theprocessor 150, the memory 152, and a database DB 156 form a noveldynamic processing engine that performs the processing activities of thesystem 102.

An example of an approach scenario is shown in FIG. 2. In illustration200, the aircraft 100 is approaching a runway 202. Runway 202 isdemarked with entry 204, exit 206, and touchdown zone 208 that begins atthe entry 204 and extends toward the exit 206. Aircraft 100 is initiallyon an approach trajectory 214. In operation of the present enhancedapproach monitor (system 102), the control module 104 references anintended approach procedure 108, generally from a NavDB, which providesa missed approach altitude (MAA 218), corresponding target angle 213, anintended configuration, and a target approach speed. In the example, theintended approach procedure includes reaching the MAA 218 with anintended approach angle 213, which occurs at a distance threshold 224.In an embodiment, the distance threshold 224 is 1 mile. The system 102references or determines these values and then constructs a trajectory212 of intended values for the aircraft 100 to take to the runway 202while meeting stabilized flight criteria.

In the example shown in FIG. 2, from location 216, the aircraft 100 ison the descent path 214, at RT angle 210; on its current trajectory, theaircraft 100 will reach the MAA 218, at a distance 222 from the entry204 of the runway 202, the location that this occurs is demarkedlocation 220 however, as described above, aircraft 100 should reach theMAA 218 ready to follow the descent path 212 at target angle 213, havethe intended configuration, and be traveling at the target approachspeed. A suitable correction for the aircraft 100 may be to correctalong potential path 215 to arrive at the MAA 218 meeting intendedobjectives.

The control module 104 continuously receives and processes a variety ofinputs from the components to which it is operationally coupled. Whiledescending from a location 216 toward the MAA 218, the control module104 continually compares the RT values to respective intended andconstructed values, as described in more detail connection with FIG. 4,method 400. The control module 104 continually determines a RT distancebetween the aircraft 100 and the runway threshold of the target runway,based on the RT location data.

The control module 104 determines when the aircraft 100 is substantiallyat the MAA 218, and when the RT distance between the aircraft 100 andthe runway threshold is less than or equal to a distance threshold. Wheneither the aircraft 100 is at the MAA 218 or the RT distance is lessthan or equal to the distance threshold 224, the aircraft 100 is inposition for descent to the runway 202, at which time the system 102recognizes whether or not a go-around scenario is underway (alsoreferred to as “recognizing the occurrence of a go-around scenario,” andan unstable scenario). As used herein, substantially means plus or minus5%, but it may be a pre-programmed or calculated value that is aircraftspecific, runway specific, or part of standard operating procedures fora selected approach operation.

The control module 104 identifies each of the following situations,individually, or in combination, as a go-around scenario: (i) when theRT speed exceeds the target approach speed, (ii) when the RTconfiguration is not equal to the intended configuration, and (iii) whenan RT approach path angle exceeds the target angle. Said differently,once the aircraft 100 has descended to the MAA 218 or it is less than orequal to the distance threshold 224 from the runway threshold,responsive to the occurrence of (i) or (ii) or (iii) individually, andresponsive to the occurrence of any combination of (i), (ii), and (iii),the control module 104 recognizes that a go-around scenario isoccurring.

When a go-around scenario is recognized, the control module 104determines whether to issue an alert. In some scenarios, the aircraft100 may be unable to perform a respective go-around operation. Forexample, the aircraft 100 may be unable to outclimb terrain if ago-around operation is initiated beyond a published Missed ApproachPoint (MAP); for example, if the MAP has been determined with safeobstacle clearance along a missed approach course. When the aircraft isunable to perform a go-around operation responsive to the recognizedgo-around scenario, the system 102 prevents issuance of a go-aroundalert to avoid an unsafe go-around operation. In various embodiments,the display system 118 additionally highlights the terrain that it hasbeen determined that the aircraft 100 may be unable to outclimb(“concerning terrain”) in a respective go-around operation. The controlmodule 104 may determine this by processing aircraft performance data114 and terrain data 124, such as, from an enhanced ground proximitywarning system (EGPWS) terrain database, or a “terrain sensitive” MAP inthe navigation database. When the aircraft 100 can perform the go-aroundoperation the control module 104 issues commands for a go-around alert.When the aircraft 100 cannot perform the go-around operation, thecontrol module 104 prevents issuance of a go-around alert.

Alerts may be issued in multiple ways. In an embodiment, the controlmodule 104 issues the go-around alert by generating commands for thedisplay system 118 to render symbols, icons, or alphanumeric informationon an image 22, and the display system 118 is configured to render thesymbols, icons, or alphanumeric information responsive to the displaycommands. In FIG. 3, an image 300, such as may be found on a primaryflight display, shows an unstable go-around alert 302 that comprisestext in a text box that is placed in the middle of the displayed image.In various embodiments, the text box may be a highlighted color orshaded with respect to the remainder of the display. In an embodiment,the primary flight display integrates a synthetic vision display, andany concerning terrain that the system 102 has determined that theaircraft 100 may be unable to outclimb in a respective go-aroundoperation is rendered in a visually distinct manner with respect toremaining terrain, for example, by highlighting the concerning terrainin red and rendering it in an alternative texture pattern from theremaining terrain on a displayed image 22. The concerning terrain may berendered similarly on other flight deck displays that present terrain,e.g. a MAP, a HUD and a vertical situation display.

The system 102 may make its determinations and selections in accordancewith a method such as method 400 of FIG. 4. With continued reference toFIGS. 1-4, a flow chart is provided for a method 400 for providing asystem 102, in accordance with various exemplary embodiments. Method 400represents various embodiments of a method for selecting an accuraterunway record. For illustrative purposes, the following description ofmethod 400 may refer to elements mentioned above in connection withFIG. 1. In practice, portions of method 400 may be performed bydifferent components of the described system. It should be appreciatedthat method 400 may include any number of additional or alternativetasks, the tasks shown in FIG. 4 need not be performed in theillustrated order, and method 400 may be incorporated into a morecomprehensive procedure or method having additional functionality notdescribed in detail herein. Moreover, one or more of the tasks shown inFIG. 4 could be omitted from an embodiment of the method 400 if theintended overall functionality remains intact.

The method starts, and at 402 the control module 104 is initialized andthe system 102 is in operation. Initialization may comprise uploading orupdating instructions and applications 160, program 162, and variouslookup tables, such as the problematic scenarios listing, stored in thedatabase 156. Stored variables may include, for example, configurable,predetermined distances thresholds, predetermined angle thresholds,predetermined amounts of time to use as time-thresholds for neighbortraffic, parameters for setting up a user interface, and the variousshapes, various colors and/or visually distinguishing techniques usedfor icons and alerts. In some embodiments, program 162 includesadditional instructions and rules for rendering information differentlybased on type of display device in display system 118. Initialization at402 may also include identifying external sources and/or externalsignals and the communication protocols to use with each of them.

At 404 the inputs are received, and the method begins to continuallyprocess them. As mentioned above, the inputs include an intendedapproach procedure 108, aircraft state data 110, terrain data 124,aircraft specific data 116 (which includes RT configuration data 112 andaircraft performance data 114), and the approach minimum data includingthe target altitude.

At 406 the method 400 determines the MAA, target angle, a targetapproach speed, and an intended configuration to accomplish thesetargets. At 408, the method 400 begins a continuous comparison of the RTlocation to a retrieved pre-programmed variable, the distance threshold224, the RT altitude to the MAA, the RT speed to the target approachspeed, and the RT approach angle to the target angle.

At 410, upon the occurrence of (a) the RT distance of the aircraft 100is substantially equal to the distance threshold 224, or (b) the RTaltitude of the aircraft 100 is substantially the MAA 218, the aircraftis at a decision point. The method 400 evaluates various go-aroundscenarios of 412, 414, and 418. As these comparisons were alreadyunderway from step 408, moving through 412, 414, and 418 is essentiallyin parallel. The go-around scenarios include: at 412, whether RT speedis greater than the target approach speed, at 414, whether the RTapproach angle is greater than the target angle, and at 418, whether theRT configuration is not equal to the intended configuration.

If any of 412, 414, and 418 are true, at least one go-around scenariohas been identified, and the method 400 determines whether the aircraft100 can perform a go-around operation based on the terrain data 124 andaircraft performance data 114. Only upon identifying at least onego-around scenario at 412, 414, or 418, and determining that theaircraft can perform the go-around operation at 418, does the method 400issue a go-around alert at 420. If the aircraft 100 cannot perform thego-around operation at 418, the method 400 prevents the issuance of thego-around alert at 422. The method 400 may continue until the aircraft100 has landed or received an override command from a user.

Thus, technologically improved alerting systems and methods for anaircraft 100 approaching a target runway are provided. As is readilyappreciated, the above examples of the system 102 are non-limiting, andmany others may be addressed by the control module 104.

Those of skill in the art will appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the embodiments disclosed herein may be implemented aselectronic hardware, computer software, or combinations of both. Some ofthe embodiments and implementations are described above in terms offunctional and/or logical block components (or modules) and variousprocessing steps. However, it should be appreciated that such blockcomponents (or modules) may be realized by any number of hardware,software, and/or firmware components configured to perform the specifiedfunctions. To clearly illustrate the interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the application and design constraints imposed onthe overall system.

Skilled artisans may implement the described functionality in varyingways for each application, but such implementation decisions should notbe interpreted as causing a departure from the scope of the presentinvention. For example, an embodiment of a system or a component mayemploy various integrated circuit components, e.g., memory elements,digital signal processing elements, logic elements, look-up tables, orthe like, which may carry out a variety of functions under the controlof one or more microprocessors or other control devices. In addition,those skilled in the art will appreciate that embodiments describedherein are merely exemplary implementations.

Further, the various illustrative logical blocks, modules, and circuitsdescribed in connection with the embodiments disclosed herein may beimplemented or performed with a general-purpose processor, a digitalsignal processor (DSP), an application specific integrated circuit(ASIC), a field programmable gate array (FPGA) or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of the method or algorithm described in connection with theembodiments disclosed herein may be embodied directly in hardware, in asoftware module executed by a controller or processor, or in acombination of the two. A software module may reside in RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, harddisk, a removable disk, a CD-ROM, or any other form of storage mediumknown in the art. An exemplary storage medium is coupled to theprocessor such that the processor can read information from, and writeinformation to, the storage medium. In the alternative, the storagemedium may be integral to the processor. The processor and the storagemedium may reside in an ASIC.

In this document, relational terms such as first and second, and thelike may be used solely to distinguish one entity or action from anotherentity or action without necessarily requiring or implying any actualsuch relationship or order between such entities or actions. Numericalordinals such as “first,” “second,” “third,” etc. simply denotedifferent singles of a plurality and do not imply any order or sequenceunless specifically defined by the claim language. The sequence of thetext in any of the claims does not imply that process steps must beperformed in a temporal or logical order according to such sequenceunless it is specifically defined by the language of the claim. When“or” is used herein, it is the logical or mathematical or, also calledthe “inclusive or.” Accordingly, A or B is true for the three cases: Ais true, B is true, and, A and B are true. In some cases, the exclusive“or” is constructed with “and;” for example, “one from the set A and B”is true for the two cases: A is true, and B is true.

Furthermore, depending on the context, words such as “connect” or“coupled to” used in describing a relationship between differentelements do not imply that a direct physical connection must be madebetween these elements. For example, two elements may be connected toeach other physically, electronically, logically, or in any othermanner, through one or more additional elements.

While at least one exemplary embodiment has been presented in theforegoing detailed description of the invention, it should beappreciated that a vast number of variations exist. It should also beappreciated that the exemplary embodiment or exemplary embodiments areonly examples, and are not intended to limit the scope, applicability,or configuration of the invention in any way. Rather, the foregoingdetailed description will provide those skilled in the art with aconvenient road map for implementing an exemplary embodiment of theinvention. It being understood that various changes may be made in thefunction and arrangement of elements described in an exemplaryembodiment without departing from the scope of the invention as setforth in the appended claims.

What is claimed is:
 1. An alerting system for an aircraft approaching atarget runway, comprising: a source of approach minimum/minima dataincluding a target altitude; a source of an intended approach procedure;a source of real time (RT) aircraft state data including an RT location,an RT altitude and an RT speed; a source of aircraft specific dataincluding RT configuration data and respective performance data; asource of terrain data; and a control module operationally coupled tothe source of approach minimum/minima data, the source of the intendedapproach procedure, the source of RT aircraft state data, the source ofaircraft specific data, and the source of terrain data, the controlmodule configured to: determine a missed approach altitude (MAA),corresponding target angle, an intended configuration, and targetapproach speed, each being related to the intended approach procedureand aircraft specific data; upon determining that the RT altitude issubstantially equal to the MAA, or a RT distance is less than or equalto a distance threshold, identify each of the following situations as ago-around scenario: (i) when the RT speed exceeds the target approachspeed, (ii) when the RT configuration is not equal to the intendedconfiguration, and (iii) when an RT approach path angle exceeds thetarget angle; and upon recognizing a go-around scenario, determinewhether the aircraft can perform a go-around operation based at least inpart upon the aircraft performance data and the terrain data; and issuea go-around alert when the aircraft can perform the go-around operation;and prevent a go-around alert when the aircraft cannot perform thego-around operation.
 2. The alerting system of claim 1, furthercomprising a display system operationally coupled to the control module,and wherein: the control module is further configured to issue thego-around alert by generating display commands for the display system torender symbology on an image; and the display system is configured torender the symbology, responsive to the display commands.
 3. Thealerting system of claim 1, wherein, when the aircraft cannot performthe go-around operation, the display system is further configured torender terrain that the aircraft may be unable to outclimb in arespective go-around operation in a visually distinct manner withrespect to remaining terrain.
 4. The alerting system of claim 1, whereinthe intended approach procedure is an instrument landing or a circlingapproach.
 5. The alerting system of claim 4, wherein the intendedapproach procedure is a precision approach.
 6. The alerting system ofclaim 4, wherein the intended approach procedure is a non-precisionapproach.
 7. The alerting system of claim 1, wherein the source of theapproach minimum data is a navigation database.
 8. The alerting systemof claim 1, wherein the source of the approach minimum data isbarometric altimeter or radio altitude reference bug data.
 9. Thealerting system of claim 1, wherein the source of the intended approachprocedure is a flight management system (FMS) or electronic chartsystem.
 10. The alerting system of claim 1, wherein substantially meansplus or minus 5 percent.
 11. The alerting system of claim 1, wherein thesource of aircraft specific data is external of the aircraft and updatedremotely.
 12. The alerting system of claim 1, further comprising a userinput device, and wherein the control module is further configured toreceive a user override command, subsequent to issuing the go-aroundalert, and cease the issuance of the go-around alert responsive thereto.13. A method for alerting for an aircraft approaching a target runway,comprising: at a control module comprising a processor and a memory,receiving, from a source of approach minimum data, a target altitude;receiving, from a flight management system (FMS), an intended approachprocedure; receiving, from a navigation system, real time (RT) aircraftstate data including an RT location, an RT altitude and an RT speed;receiving from an avionics system, RT configuration data; receivingaircraft specific data including configuration data and respectiveperformance data; receiving terrain data from a terrain database;determining a missed approach altitude (MAA), corresponding targetangle, an intended configuration, and target approach speed, each beingrelated to the intended approach procedure and aircraft specific data;upon determining that there is (a) an occurrence of the RT altitude issubstantially equal to the MAA, or (b) a RT distance of less than orequal to a distance threshold, identify each of the following situationsas a go-around scenario: (i) when the RT speed exceeds the targetapproach speed, (ii) when the RT configuration is not equal to theintended configuration, and (iii) when an RT approach path angle exceedsthe target angle; and upon recognizing the occurrence of a go-aroundscenario, determining whether the aircraft can perform a go-aroundoperation based at least in part upon the aircraft performance data andthe terrain data; and issuing a go-around alert when the aircraft canperform the go-around operation; and preventing a go-around alert whenthe aircraft cannot perform the go-around operation.
 14. The method ofclaim 13, further comprising: generating display commands for a displaysystem to render symbology on an image; and rendering the symbology onthe display system, responsive to the display commands.
 15. The methodof claim 14, further comprising receiving a user override command,subsequent to issuing the go-around alert; and ceasing the issuance ofthe go-around alert responsive thereto.
 16. An enhanced approachmonitor, comprising: a source of approach minimum data including atarget altitude; a source of an intended approach procedure; a source ofreal time (RT) aircraft state data including an RT location, an RTaltitude and an RT speed; a source of aircraft specific data includingRT configuration data and respective performance data; a source ofterrain data; and a control module operationally coupled to the sourceof approach minimum data, the source of the intended approach procedure,the source of RT aircraft state data, the source of aircraft specificdata, and the source of terrain data, the control module configured to:determine a missed approach altitude (MAA), corresponding target angle,an intended configuration, and target approach speed, each being relatedto the intended approach procedure and aircraft specific data; upondetermining that the RT altitude is substantially equal to the MAA, or aRT distance is less than or equal to a distance threshold, identify eachof the following situations as a go-around scenario: (i) when the RTspeed exceeds the target approach speed, (ii) when the RT configurationis not equal to the intended configuration, and (iii) when an RTapproach path angle exceeds the target angle; and upon recognizing theoccurrence of a go-around scenario, determine whether the aircraft canperform a go-around operation based at least in part upon the aircraftperformance data and the terrain data; and issue a go-around alert whenthe aircraft can perform the go-around operation; and prevent ago-around alert when the aircraft cannot perform the go-aroundoperation; and a display system operationally coupled to the controlmodule, and wherein: the control module is further configured to issuethe go-around alert by generating display commands for the displaysystem to render symbology on an image; and the display system isconfigured to render the symbology, responsive to the display commands.